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ENGINEERING (1124 journals)            First | 5 6 7 8 9 10 11 12 | Last

MATEC Web of Conferences     Open Access  
Matériaux & Techniques     Full-text available via subscription   (1 follower)
Mathematical Models and Methods in Applied Sciences     Hybrid Journal   (3 followers)
Mathematical Problems in Engineering     Open Access   (4 followers)
Mathematics of Control, Signals, and Systems (MCSS)     Hybrid Journal   (3 followers)
Mauerwerk     Hybrid Journal  
Measurement     Hybrid Journal   (1 follower)
Measurement Science Review     Open Access   (1 follower)
Meccanica     Hybrid Journal   (1 follower)
Mechatronics     Hybrid Journal   (3 followers)
Medical and Biological Engineering and Computing     Hybrid Journal   (2 followers)
Medical Engineering & Physics     Hybrid Journal   (9 followers)
Membrane Science and Technology     Full-text available via subscription   (2 followers)
Membrane Technology     Full-text available via subscription   (1 follower)
Memetic Computing     Hybrid Journal  
Metal Powder Report     Full-text available via subscription   (2 followers)
Metallurgist     Hybrid Journal   (2 followers)
Metaphysica     Hybrid Journal   (1 follower)
Metascience     Hybrid Journal   (1 follower)
Metrologia     Full-text available via subscription   (1 follower)
Microelectronic Engineering     Hybrid Journal   (4 followers)
Microelectronics International     Hybrid Journal  
Microelectronics Journal     Hybrid Journal   (3 followers)
Microelectronics Reliability     Hybrid Journal   (5 followers)
Microfluidics and Nanofluidics     Hybrid Journal   (9 followers)
Micromachines     Open Access   (1 follower)
MNASSA : Monthly Notes of the Astronomical Society of South Africa     Full-text available via subscription   (1 follower)
Modelling and Simulation in Engineering     Open Access   (4 followers)
Modern Applied Science     Open Access   (1 follower)
Molecular BioSystems     Full-text available via subscription   (1 follower)
Molecular Engineering     Hybrid Journal  
Molecular Pharmaceutics     Full-text available via subscription   (6 followers)
MRS Bulletin     Full-text available via subscription   (4 followers)
MRS Online Proceedings     Full-text available via subscription   (1 follower)
Multiagent and Grid Systems     Hybrid Journal  
Multidimensional Systems and Signal Processing     Hybrid Journal  
NANO     Hybrid Journal   (6 followers)
Nano Letters     Full-text available via subscription   (37 followers)
Nano Research     Hybrid Journal   (3 followers)
Nano Reviews     Open Access   (15 followers)
Nanopages     Full-text available via subscription   (1 follower)
Nanoscale and Microscale Thermophysical Engineering     Hybrid Journal   (3 followers)
Nanoscale Systems : Mathematical Modeling, Theory and Applications     Open Access  
Nanotechnologies in Russia     Hybrid Journal   (1 follower)
Nanotechnology     Partially Free   (8 followers)
Nanotechnology Magazine, IEEE     Full-text available via subscription   (12 followers)
Nanotechnology Reviews     Full-text available via subscription   (4 followers)
Natural Hazards     Hybrid Journal   (99 followers)
Nature Nanotechnology     Full-text available via subscription   (41 followers)
Naval Engineers Journal     Hybrid Journal   (3 followers)
NDT & E International     Hybrid Journal   (10 followers)
Nexo Revista Científica     Open Access  
Nigerian Journal of Technological Research     Full-text available via subscription  
Nigerian Journal of Technology     Full-text available via subscription  
NIR news     Full-text available via subscription  
Nonlinear Dynamics     Hybrid Journal   (5 followers)
Nonlinear Engineering : Modeling and Application     Full-text available via subscription   (1 follower)
Nonlinearity     Full-text available via subscription   (2 followers)
Nova Scientia     Open Access  
NTM Zeitschrift für Geschichte der Wissenschaften, Technik und Medizin     Hybrid Journal   (4 followers)
Nuclear Engineering and Design     Hybrid Journal   (11 followers)
Numerical Algorithms     Hybrid Journal   (3 followers)
Numerical Heat Transfer, Part A: Applications: An International Journal of Computation and Methodology     Hybrid Journal   (3 followers)
Numerical Heat Transfer, Part B: Fundamentals: An International Journal of Computation and Methodology     Hybrid Journal   (5 followers)
Ocean Science Journal     Hybrid Journal   (3 followers)
Oil and Gas Journal     Full-text available via subscription   (10 followers)
Online Journal for Global Engineering Education     Open Access  
Open Journal of Fluid Dynamics     Open Access   (3 followers)
Open Journal of Safety Science and Technology     Open Access   (2 followers)
Operations Research Letters     Hybrid Journal   (4 followers)
Optical Communications and Networking, IEEE/OSA Journal of     Hybrid Journal   (3 followers)
Optimization and Engineering     Hybrid Journal   (2 followers)
Opto-Electronics Review     Hybrid Journal   (1 follower)
OR Spectrum     Hybrid Journal  
Organic Electronics     Hybrid Journal   (3 followers)
Ozone Science & Engineering     Hybrid Journal   (1 follower)
Papers In Regional Science     Hybrid Journal   (6 followers)
Particle & Particle Systems Characterization     Hybrid Journal  
Particulate Science and Technology: An International Journal     Hybrid Journal   (1 follower)
Perspectives on Science     Hybrid Journal   (4 followers)
Pesquisa Operacional     Open Access  
Pest Management Science     Hybrid Journal   (4 followers)
Petroleum Science     Full-text available via subscription   (2 followers)
Phase Transitions: A Multinational Journal     Hybrid Journal  
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences     Full-text available via subscription   (7 followers)
Photonics Journal, IEEE     Full-text available via subscription   (5 followers)
Physica B: Condensed Matter     Hybrid Journal   (4 followers)
Physica C: Superconductivity     Hybrid Journal  
Physica D: Nonlinear Phenomena     Hybrid Journal   (3 followers)
Physics of Fluids     Hybrid Journal   (18 followers)
Planning News     Full-text available via subscription   (3 followers)
Plasma Devices and Operations     Hybrid Journal   (3 followers)
Plasma Science and Technology     Full-text available via subscription   (2 followers)
Plasmonics     Hybrid Journal  
Platinum Metals Review     Open Access   (2 followers)
Polar Research     Open Access   (1 follower)
Polar Science     Hybrid Journal   (3 followers)
Polímeros: Ciência e Tecnologia     Open Access   (1 follower)
Polish Maritime Research     Open Access  
Polymer Engineering & Science     Hybrid Journal   (12 followers)

  First | 5 6 7 8 9 10 11 12 | Last

Reactive and Functional Polymers    [5 followers]  Follow    
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 1381-5148
     Published by Elsevier Homepage  [2556 journals]   [SJR: 0.834]   [H-I: 55]
  • Synthesis and Investigation of a Photosensitive, Europium-containing
           Polymer
    • Abstract: Publication date: Available online 17 January 2014
      Source:Reactive and Functional Polymers
      Author(s): Shuqi Fan , Xu Fei , Xiuying Wang , Jing Tian , Longquan Xu , Peng Yang , Yi Wang
      A series of europium complexes containing polymeric reactivity groups have been successfully synthesized using a simple method. Among them, Eu(DBM)2(Phen)(MA), which has the best fluorescence properties and solubility, was polymerized with glycidyl methacrylate (GMA) for use as a novel UV-written polymer material. The Poly (GMA-co-Eu(DBM)2(Phen)(MA)) containing different proportions of europium were prepared, and their spectroscopic properties were investigated in detail. Polymer films with optimum proportions (a molar ratio between GMA and Eu(DBM)2(Phen)(MA) of 15) exhibited good UV light lithograph sensitivities, strong visible fluorescence intensities, high glass transition temperatures (Tg: > 170 °C), good thermal stabilities (Td: up to 295 °C) and solvent resistances after crosslinking. Micro patterns with smooth top surfaces were fabricated from the resulting polymer by using direct UV exposure and chemical development.
      Graphical abstract image Highlights The photosensitive europium-containing polymers display excellent thermal stability, UV light lithograph sensitivity and strong visible fluorescence intensity. The micro patterns fabricated from the europium-containing polymer by direct UV exposure have good chemical resistance.

      PubDate: 2014-01-20T10:34:30Z
       
  • Preparation of polymeric macroporous hydrogels for the immobilization of
           enzymes using an emulsion-gelation method
    • Abstract: Publication date: Available online 17 January 2014
      Source:Reactive and Functional Polymers
      Author(s): Ryuichi Sato , Takuro Kawakami , Hideaki Tokuyama
      Novel polymeric macroporous hydrogels were developed to entrap and immobilize lipase. Poly(ethylene glycol) methyl ether acrylate hydrogel was used as the support. The emulsion-gelation method using oil-in-water emulsions was used to simultaneously synthesize the hydrogels and entrap lipase in the randomly distributed, non-interconnected, sphere-like macropores, which were several micrometers in diameter. The lipase, immobilized within the macroporous hydrogel, successfully catalyzed the hydrolysis of triacetin without leakage of lipase or loss of activity during repeated use. The macroporous hydrogel-immobilized lipase exhibited higher activity than the lipase immobilized within a non-porous hydrogel, which indicates entrapment of lipase in the macropores without interference from the polymer and excellent diffusional permeability of macroporous hydrogel to substrate/product species.


      PubDate: 2014-01-20T10:34:30Z
       
  • Editors and Editorial Board
    • Abstract: Publication date: February 2014
      Source:Reactive and Functional Polymers, Volume 75




      PubDate: 2014-01-20T10:34:30Z
       
  • A facile construction method for pH and oxidation dual-responsive assembly
           based on ferrocene-modified chitooligosaccharide
    • Abstract: Publication date: Available online 31 December 2013
      Source:Reactive and Functional Polymers
      Author(s): Liang Wang , Ya-Kun Li , Youqian Xu , Cai-Qi Wang
      Here, we present a novel and facile method for constructing “snowflake-like” assemblies that respond to external stimuli, similar to snowflakes in nature, via the self-organization of ferrocene-modified chitooligosaccharide (FcCOS) in an acid aqueous solution. Interestingly, the snowflakes were sensitive to pH and redox stimuli. They not only formed irregular network-like aggregates when the pH was adjusted to 7.0, they also gradually transformed into loose snowflakes with holes after exposure to air for 5 d and totally collapsed after treatment with hydrogen peroxide. Due to their interesting responses to pH and oxidation, these assemblies are a very interesting and promising system for biomaterial applications.


      PubDate: 2014-01-04T12:01:01Z
       
  • Cycloodepolymerization as a Method for the Synthesis of Macrocyclic
           Oligomers
    • Abstract: Publication date: Available online 31 December 2013
      Source:Reactive and Functional Polymers
      Author(s): Philip Hodge
      Macrocyclic oligomers (MCOs) are important as starting materials for Entropically-driven Ring-opening Polymerizations (ED-ROPs). This article reviews the preparation of MCOs by the Cyclo-depolymerization (CDP) of condensation polymers. Many MCOs have been prepared successfully this way and in numerous cases individual macrocycles have been isolated. This approach can provide one-step syntheses of many macrocycles. The combination of CDP plus ED-ROP is an attractive potential method for recycling (‘Ring-chain Recycling’) many condensation polymers.


      PubDate: 2014-01-04T12:01:01Z
       
  • Preparation and characterization of an IPN type chelating resin containing
           amino and carboxyl groups for removal of Cu(II) from aqueous solutions
    • Abstract: Publication date: Available online 22 December 2013
      Source:Reactive and Functional Polymers
      Author(s): Serkan Emik
      A novel IPN type chelating resin, amino-functionalized poly (glycidyl methacrylate)/ poly (acrylic acid), (pGMA/pAA), was synthesized by a combination of serial reactions including, conventional radical polymerization, amination and photopolymerization. To assess the efficacy and characteristics of the resin in removal of Cu (II), batch adsorption experiments were carried out, and the effects of different parameters such as contact time, adsorbent dosage, initial metal ion concentration, temperature, and pH on the adsorption process were investigated. The results showed that 0.5g/L dosage and pH 5 are the optimum values to achieve the maximum adsorption capacity and the adsorption kinetic of Cu (II) was well represented by pseudo-second-order kinetic model. In addition, it was found that the adsorption was mainly controlled by the film diffusion mechanism, along with a considerable contribution of the intra-particle diffusion mechanism, and Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherm models can be used for interpreting the adsorption process. Moreover, FT-IR analysis results and the mean free energies of adsorption clearly indicate that the ion exchange and chelation mechanisms took place as dominating mechanisms simultaneously during the adsorption process. It was also found to be that IPN resin could be used at least four times without losing its original activity.


      PubDate: 2013-12-23T10:33:58Z
       
  • Synthesis and self-assembly of carbazole-based amphiphilic triblock
           copolymers with aggregation-induced emission enhancement
    • Abstract: Publication date: Available online 21 December 2013
      Source:Reactive and Functional Polymers
      Author(s): Guang Li , Fanfan Du , Hu Wang , Ruke Bai
      Well-defined amphiphilic triblock copolymers with carbazole pendants (PVACB-PEG2000-PVACB) were synthesized via the combination of reversible addition-fragmentation chain transfer (RAFT) polymerization and “click” chemistry. All of the intermediate and final products were characterized using 1H NMR, FT-IR and GPC. Cup-shaped vesicles were then fabricated via self-assembly of the carbazole-containing amphiphilic triblock copolymers in aqueous solution, which were characterized by TEM and SEM. These novel carbazole-based polymeric vesicles were found to exhibit interesting aggregation-induced emission enhancement (AIEE) characteristics compared with the fluorescence intensity of the polymers in organic solution.


      PubDate: 2013-12-23T10:33:58Z
       
  • One-pot Synthesis of Poly(triazole-graft-caprolactone) via Ring-Opening
           Polymerization Combined with Click Chemistry as a Novel Strategy for Graft
           Copolymers
    • Abstract: Publication date: Available online 16 December 2013
      Source:Reactive and Functional Polymers
      Author(s): Fusun Seyma Gungor , Baris Kiskan
      The one-pot construction of polytriazole grafted with poly(ε-caprolactone) via the polymerization of 4-azido-1-(prop-2-yn-1-yloxy)butan-2-ol (N3hydroxypropargyl) and ε-caprolactone monomers is reported. For this purpose, a click reaction and ring-opening polymerization (ROP) were combined and carried out simultaneously. N3hydroxypropargyl served as both the ROP initiator and a monomer for the click polymerization. Thus, an in situ “grafting-through and from” strategy was established in one pot. CuBr and Sn(Oct)2 were utilized as dual catalysts, and the polymerization reactions were carried out at 120 °C under a N2 atmosphere.


      PubDate: 2013-12-19T10:31:49Z
       
  • Protein-polymer hybrid oil-absorbing gel using hair keratin as
           macroinitiator by SET-LRP
    • Abstract: Publication date: Available online 17 December 2013
      Source:Reactive and Functional Polymers
      Author(s): Lijun Fan , Hou Chen , Shilong Wei , Fujun Cao
      Biological macroinitiator for single electron transfer-living radical polymerization was designed from extracted human hair keratin by nucleophilic reaction of amino group with 2-bromoisobutyryl bromide. Homogeneous polymer-protein hybrid oil-absorbing gel was synthesized by copolymerization of acrylate with a small amount of cross-linker using keratin-Br macroinitiator. The variation of gelation properties including gelation time, gel fraction and oil absorbency was studied by changing monomer composition, initiator type, and cross-linker structure. The gelation time did not change significantly by varying the substitution degree of macroinitiator. Aromatic cross-linker was more prone to form microgel and higher oil absorbency was achievable with longer oleophilic chain of acrylate. The polymer-protein was obtained with the maximum oil absorption of chloroform reaching 43.7 g g-1 and performed good reusability.


      PubDate: 2013-12-19T10:31:49Z
       
  • Preparation of poly(acrylic acid)/starch hydrogel and its application for
           cadmium ion removal from aqueous solutions
    • Abstract: Publication date: Available online 12 December 2013
      Source:Reactive and Functional Polymers
      Author(s): E.S. Abdel-Halim , Salem S. Al-Deyab
      In this paper, potassium bromate/thiourea dioxide redox system was used to initiate the graft copolymerization reaction of acrylic acid onto maize starch. The so obtained polyacrylic acid/starch graft copolymer was crosslinked by further treatment with alkaline epichlorohydrin to get three dimensional hydrogel. This crosslinked hydrogel was used for the removal of the heavy element, Cd2+ from its aqueous solution by adsorption. All factors which are expected to affect the adsorption process, like adsorbent concentration, immersion time, graft yield of the adsorbent, Cd2+ concentration and adsorption temperature were extensively studied and reported in the text. The study and investigations demonstrated that the adsorption efficiency is affected by the adsorbent graft yield and the adsorption medium temperature. In addition, on fitting the data obtained from the adsorption process, it was found that the adsorption obeys both Langmuir and Freundlich adsorption isotherms but the Langmuir isotherm shows better mathematical fitting for the equilibrium data than does Freundlich model, based on the higher R2 value for the Langmuir isotherm.


      PubDate: 2013-12-15T19:31:08Z
       
  • Editors and Editorial Board
    • Abstract: Publication date: January 2014
      Source:Reactive and Functional Polymers, Volume 74




      PubDate: 2013-12-15T19:31:08Z
       
  • How the interactions with humic acids affect the mobility of ionic dyesin
           hydrogels - 2.Non-stationary diffusion experiments
    • Abstract: Publication date: Available online 12 December 2013
      Source:Reactive and Functional Polymers
      Author(s): Petr Sedláček , Jiří Smilek , Martina Klučáková
      Non-stationary diffusion of two cationic dyes (Methylene Blue and Rhodamine 6G) was studied in hydrogels with different content of agarose and humic acids (HA). A simple spectrophotometrical method was utilized in the in situ measurement of dye concentration in the gel samples at different distances from the boundary. The effect of temperature, pH and ionic strength was investigated. The results confirmed the considerable partitioning of both dyes in agarose gels as well as the strong immobilization of dyes caused by their sorption on HA. The apparent diffusion coefficients of both dyes decreased with increasing solid content in gels. In the case of agarose gels without the addition of HA, this decrease was attributed to increased tortuosity of diffusion caused by denser agarose network. The apparent equilibrium constant of the sorption of dyes on HA in agarose/HA gels was calculated from their apparent diffusion coefficients. The value of the equilibrium constant increased with the content of HA in gel and, surprisingly, also with decreasing pH inside gel.


      PubDate: 2013-12-15T19:31:08Z
       
  • Synthesis of CO2-Responsive Polymers by Post-Polymerization Modification
    • Abstract: Publication date: Available online 6 December 2013
      Source:Reactive and Functional Polymers
      Author(s): P. Schattling , I. Pollmann , P. Theato
      We describe a general method to synthesize a double responsive polymer, exhibiting a temperature and CO2 responsive behavior. The polymer derived from a controlled radical polymerization technique of pentafluorophenyl acrylate (PFPA), followed by a sequential post-polymerization modification of a CO2 responsive- and thermo-responsive amines. Utilizing this approach three double responsive copolymers were synthesized, poly(3-N’,N’-dimethylaminopropyl acrylamide-co-N-isopropyl acrylamide) (poly(DMPA-co-NIPAM)), poly(L-Arginine methyl ester acrylamide-co-N-isopropyl acrylamide) (poly(AME-co-NIPAM)) and poly(L-Arginine methyl ester acrylamide-co-N-cyclopropyl acrylamide) (poly(AME-co-CPAM), respectively. Utilizing turbidity measurement, the stimuli responsiveness of the polymers were investigated and it was found that the lower critical solution temperature (LCST) could be reversibly triggered over a wide temperature range between 6 and 15°C by purging with CO2 and Ar, respectively. The presented strategy allows the introduction of different functionalities and the control of their fractional amount at the same time and proofs as a versatile platform, leading to adjustable functional polymers.
      Graphical abstract image

      PubDate: 2013-12-11T14:56:24Z
       
  • Bisensitive core-shell nanohydrogels by e-beam irradiation of micelles
    • Abstract: Publication date: Available online 7 December 2013
      Source:Reactive and Functional Polymers
      Author(s): Lorenzo.A. Picos-Corrales , Angel Licea-Claveríe , Karl-Friedrich Arndt
      Sensitive nanohydrogels based on micellar aggregates from amphiphilic block copolymers were synthesized by means of electron beam irradiation. The crosslinked shell consists of temperature sensitive [N-isopropylacrylamide (NIPAAm)] and pH sensitive [5-methacryloyloxy pentatonic acid (5MPA) or 4-methacryloyloxy benzoic acid (4MBA)] units, while the core is a hydrophobic network that may work as a reservoir for drugs. The effect of the irradiation dose and the polymer concentration were tested. Dynamic and static light scattering were combined to investigate the morphology of aggregates prior and after irradiation to obtain nanohydrogels. Hydrodynamic radius of nanogels is in the range from 18 to 44 nm. ρ-Parameter suggests that crosslinked aggregates of flexible chains were obtained. Mixtures of block copolymers with different phase transition behavior in each aggregate lead to the preparation of nanohydrogels with tailored phase transition behavior.


      PubDate: 2013-12-11T14:56:24Z
       
  • Synthesis of Core-Fluorescent Four-Armed Star and Dicyclic 8-Shaped
           Poly(THF)s by Electrostatic Self-assembly and Covalent Fixation (ESA-CF)
           Protocol
    • Abstract: Publication date: Available online 7 December 2013
      Source:Reactive and Functional Polymers
      Author(s): Susumu Fujiwara , Takuya Yamamoto , Yasuyuki Tezuka , Satoshi Habuchi
      A pair of four-armed star and dicyclic 8-shaped poly(tetrahydrofuran)s, poly(THF)s, possessing a perylene diimide group at the core position (Ia and Ib, respectively) were synthesized by means of an electrostatic self-assembly and covalent fixation (ESA-CF) protocol. Mono- and bifunctional poly(THF)s having N-phenylpiperidinium salt end groups accompanying a perylene diimide tetracarboxylate as a counteranion were prepared by the ion-exchange reaction, and the subsequent covalent conversion by reflux in toluene afforded the corresponding core-fluorescent four-armed star and dicyclic 8-shaped poly(THF)s, (Ia and Ib) for the use of single-molecule fluorescence microscopy measurements.


      PubDate: 2013-12-11T14:56:24Z
       
  • Facile synthesis of 3-(ω-acetoxyalkyl)thiophenes and derived
           copolythiophenes using Rieke zinc
    • Abstract: Publication date: Available online 7 December 2013
      Source:Reactive and Functional Polymers
      Author(s): Suleyman Kudret , Jurgen Kesters , Sander Janssen , Niko Van den Brande , Maxime Defour , Bruno Van Mele , Jean Manca , Laurence Lutsen , Dirk Vanderzande , Wouter Maes
      An optimized synthetic protocol toward highly reactive Rieke zinc is applied for the preparation of a series of ω-(2,5-dibromothiophene-3-yl)alkyl acetate monomers and statistical copolythiophenes derived thereof, with 10% of ester-functionalized side chains. The obtained conjugated polymers are attractive electron donor materials for organic solar cells, notably to increase the thermodynamic stability of the bulk heterojunction polymer:fullerene active layer blend, and are fully characterized by a combination of spectroscopic, thermal analysis and electrochemical techniques.
      Graphical abstract image

      PubDate: 2013-12-11T14:56:24Z
       
  • Antibacterial dental resin composites
    • Abstract: Publication date: Available online 7 December 2013
      Source:Reactive and Functional Polymers
      Author(s): Nurit Beyth , Shady Farah , Abraham J. Domb , Ervin I. Weiss
      Resin composite materials exhibit good esthetic properties and strength, making them the most commonly used materials for restoring hard tissue, i.e., enamel and dentin. In the last 30 years these restorative materials have been widely used for both anterior and posterior restorations. Regrettably, studies have indicated numerous failures, the main reason for which is secondary caries. Resin composites were found to accumulate more dental plaque than enamel and other restorations. Thus, to increase the service life of resin composite restorations, modifications introducing antibacterial properties are required. In this review the authors discuss the advantages and disadvantages of various released and non-released antibacterial agents incorporated in resin composites. A change in strategy based on the use of antimicrobial polymeric macromolecules is suggested, focusing on polycationic antimicrobials. Polyethyleneimine nanoparticles, in particular, are presented as a possible solution to the disadvantages of released antiseptic agents. Developing agents with strong antimicrobial activity upon contact that do not diminish over time nor affect the biocompatibility of materials should be the focus of future research.


      PubDate: 2013-12-11T14:56:24Z
       
  • The polymerization behavior and thermal properties of benzoxazine based on
           o-allylphenol and 4,4’-diaminodiphenyl methane
    • Abstract: Publication date: Available online 9 December 2013
      Source:Reactive and Functional Polymers
      Author(s): Yanfang Liu , Chunyan Liao , Zhanzhan Hao , Xinxin Luo , Sisi Jing , Mingtao Run
      Three bifunctional benzoxazines (oAP-ddm, oC-ddm, and P-ddm) were synthesized from 4,4’-diaminodiphenyl methane, formaldehyde, and three phenols, namely o-allylphenol, o-cresol, and phenol. The polymerization temperatures and activation energies of oAP-ddm and oC-ddm are very similar and higher than those of P-ddm; however, their reaction enthalpies exhibit inverse behavior. The storage moduli of the corresponding polybenzoxazines, PoAP-ddm, PoC-ddm, and PP-ddm, are approximately 2.1, 3.2, and 2.9 GPa at 25 °C, respectively, and their glass transition temperatures are 139, 166, and 198 °C, respectively. The thermal stabilities of PoAP-ddm and PoC-ddm are similar and lower than that of PP-ddm. The results indicate that polybenzoxazines based on ortho-substituted phenols provide higher flexibility than their counterparts prepared from unsubstituted phenol.


      PubDate: 2013-12-11T14:56:24Z
       
  • Synthesis and characterization of Aza222-based polymers for the removal of
           mercury from aqueous solutions
    • Abstract: Publication date: January 2014
      Source:Reactive and Functional Polymers, Volume 74
      Author(s): Mikhail Y. Redko , Karrie M. Manes , Julian S. Taurozzi , James E. Jackson , Volodymyr V. Tarabara
      Polymeric materials for mercury complexation have been prepared by cross-linking 1,4,7,10,13,16,21,24-octaazabicyclo[8.8.8]hexacosane (H6Aza222) with α,α′-dichloro-p-xylene and other multidentate electrophiles. Bulk and microporous p-xylylene-Aza222 were shown to be effective at binding divalent mercury cations from aqueous solutions of HgCl2 or Na2HgI4. The complexants were regenerable using solutions of HCl or Na2S.


      PubDate: 2013-12-07T10:34:35Z
       
  • A Method for Preparing Water Soluble Cyclic Polymers
    • Abstract: Publication date: Available online 1 December 2013
      Source:Reactive and Functional Polymers
      Author(s): Shiyu Long , Qingquan Tang , Ying Wu , Luoxin Wang , Ke Zhang , Yongming Chen
      A novel ring-closure method was developed to specifically focus on the preparation of water soluble cyclic polymers. The well-defined linear polymers were synthesized by a standard RAFT polymerization using a functional RAFT agent 1. The cyclic polymers were then obtained by virtue of an efficient bromomaleimide-thiol substitution reaction to ring-close the linear precursors. This technique is unique in that it not only produces various well-defined water soluble cyclic polymers with high efficiency and topology purity, but also employs the environmentally benign solvent, water, as the ring-closure reaction media.


      PubDate: 2013-12-03T10:34:51Z
       
  • A facile route to obtain an acidic hydrogel containing lactate moieties
    • Abstract: Publication date: Available online 22 November 2013
      Source:Reactive and Functional Polymers
      Author(s): Jing Xu , Congming Xiao
      The idea to develop hydrophilic lactic acid-based polyelectrolyte was presented. A facile route was utilized to prepare smart hydrogels that contained lactate units and carboxylic groups. The hydrogels were obtained through the radical cross-linking reaction between an unsaturated lactate-contained macromonomer and acrylic acid (AA)/itaconic acid (IA) monomer pair. The structure and performances of the hydrogels were characterized with thermogravimetric analysis, dynamic thermal analysis, scanning electron microscopy, swelling tests and adsorption measurements. The equilibrium swelling ratios of the hydrogels in acidic (pH 3.6) and basic (pH 11.5) media reached 25.3 and 62.3 respectively. The pH-sensitive swelling behaviors of the hydrogel confirmed that the hydrogels contained carboxylic groups and they were hydrophilic. The metal ions including calcium, copper, lead and cerium ions were bound into the hydrogels, which also confirmed the existence of the carboxyl groups. Moreover, the swelling ratio and adsorption capacity of the gel prepared from monomer pair were significantly higher than those obtained in absence of IA, which suggested that the properties of the hydrogels could be controllable by simply adjusting the ratio of AA/IA. In addition, the weight loss percentage of the hydrogel was around 37% after two-week in vitro degradation, which indicated the hydrogel contained lactate units.


      PubDate: 2013-11-25T10:34:41Z
       
  • Self-Diffusion in Asymmetric Ring-Linear Blends
    • Abstract: Publication date: Available online 23 November 2013
      Source:Reactive and Functional Polymers
      Author(s): Steven F. Henke , Sachin Shanbhag
      We use the bond-fluctuation model to measure self-diffusivity of asymmetric blends of cyclic and linear polymers, where the number of monomers in the cyclic and linear polymer are different. We consider two series of asymmetric blends and vary the relative composition. In particular, N C = 300 and N L = 150 , and N C = 150 and N L = 300 , where N C and N L are the number of monomers in the cyclic and linear polymers, respectively. Compared to cyclic polymers, the self-diffusivity of linear polymers is relatively insensitive to the blend composition, and is approximately within a factor of two of the pure linear self-diffusivity. In sharp contrast, the self-diffusivity of cyclic polymers exhibits a strong “order of magnitude” variation with the blend microenvironment. The latter data appear to be consistent with trends expected from previous simulations of symmetric cyclic-linear blends, as a function of the fraction of linear polymer.


      PubDate: 2013-11-25T10:34:41Z
       
  • Synthesis of PEG Containing Cationic Block Copolymers and their
           Interaction with Human Serum Albumin
    • Abstract: Publication date: Available online 19 November 2013
      Source:Reactive and Functional Polymers
      Author(s): Rakesh Banerjee , Swapnil Gupta , Debabrata Dey , Souvik Maiti , Dibakar Dhara
      In this study, we have demonstrated the synthesis of a new series of cationic homopolymers based on 3-methacrylamidopropyl)-trimethylammonium chloride (MAPTAC) and block copolymers based on MAPTAC and poly(ethylene glycol) methyl ether acrylate (PEGMA), with the aim of studying their interactions with human serum albumin (HSA). The homopolymer (PMAPTAC) and its block copolymers containing 69 and 84 mol% PEGMA (PMAPTAC-b-PPEGMA69 and PMAPTAC-b-PPEGMA84 respectively) were prepared by RAFT technique. Interactions between human serum albumin (HSA) and these cationic polymers were studied using fluorescence spectroscopy, along with isothermal titration calorimetry (ITC) and circular dichroism (CD). The fluorescence spectra of these protein-polymer complexes revealed considerable binding affinity between PMAPTAC and HSA. However, the block copolymers exhibited relatively lower binding affinities with HSA that decreased with increase in PEGMA block length. CD studies corroborated the fluorescence data by suggesting the formation of protein-polymer complex that led to considerable loss in the negative ellipticity of HSA resulting from partial unfolding of the polypeptide chain. However, in case of the block copolymers, the presence of PEG partly prevented the perturbation of the polypeptide chain induced by polymer-protein interactions. ITC data suggested that the binding was an entropy-driven process. GdmCl denaturation curves showed increased stability of native HSA in presence of PMAPTAC, indicating higher conformational stability of HSA in presence of the cationic homopolymer.
      Graphical abstract image

      PubDate: 2013-11-21T10:34:07Z
       
  • Novel Approach for Attapulgite/Poly(acrylic acid) (ATP/PAA) Nanocomposite
           Microgels as Selective Adsorbent for Pb(II) Ion
    • Abstract: Publication date: Available online 19 November 2013
      Source:Reactive and Functional Polymers
      Author(s): Peng Liu , Liping Jiang , Longxiang Zhu , Aiqin Wang
      A novel approach was developed for the preparation of the attapulgite/poly(acrylic acid) (ATP/PAA) nanocomposite microgels via the “one-pot” inverse suspension radical polymerization of acrylic acid (AA) with the multi-functionalized attapulgite nanorods (org-ATP) as the sole crosslinker. The parameters of the feeding ratio of the functional attapulgite (org-ATP) nanorods and AA (org-ATP/AA), oil (liquid paraffin)-water ratio, and feeding ratios of dispersing agent (sodium dodecyl benzene sulfonate (SDBS)) and initiator (ammonium persulfate (APS)) were optimized via 4-Variable 3-Level Orthogonal experiments. Under the optimized preparation condition, more than 85% of the monomer AA had been grafted onto the org-ATP nanorods to form the 3-dimensional network of the ATP/PAA nanocomposite microgel. The ATP/PAA nanocomposite microgel exhibited better mechanical stabilities (resistance to pressure and resistance to agitation) and selective adsorption to heavy metal ions, especially to Pb2+. The adsorbed Pb2+ ion could be completely eluted with HCl solution. The better mechanical stability and regeneration make it potential adsorbent for the heavy metal contaminated water.


      PubDate: 2013-11-21T10:34:07Z
       
  • Mechanical properties of pH-responsive poly(2-hydroxyethyl
           methacrylate/methacrylic acid) microgels prepared by inverse microemulsion
           polymerization
    • Abstract: Publication date: Available online 21 November 2013
      Source:Reactive and Functional Polymers
      Author(s): Wei Hou , Shen YingHua , Hui-Min Liu , Aiqin Zhang , Sheng Dai
      The structure and mechanical properties of monodisperse pH-responsive poly(2-hydroxyethyl methacrylate/methacrylic acid) (Poly(HEMA/MAA)) microgels prepared by inverse microemulsion polymerization were systematically investigated. To facilitate the polymerization, the inverse microemulsion systems were first optimized by generating relevant pseudo-three-component phase diagrams. The reactivity ratios of HEMA (r 1 = 1.001±0.064) and MAA (r 2 = 0.318±0.035) determined by titration method suggested that PHEMA segments preferred to be localized in the core of the synthesized Poly(HEMA/MAA)) microgels. The mechanical property studies of the microscopic Poly(HEMA/MAA)) microgels from oscillation rheometry revealed that microgel composition, concentration and pH could significantly alter the elastic modulus (G’), and a maximum averaged elastic modulus (G ave’) value of about 8.2×103 Pa was obtained.


      PubDate: 2013-11-21T10:34:07Z
       
  • Nucleation, crystallization, self-nucleation and thermal fractionation of
           cyclic and linear poly(ε-caprolactone)s
    • Abstract: Publication date: Available online 19 November 2013
      Source:Reactive and Functional Polymers
      Author(s): R.A. Pérez , M.E. Córdova , J.V. López , J.N. Hoskins , B. Zhang , S.M. Grayson , A.J. Müller
      A series of low polydispersity cyclic PCL samples (C-PCLs), as well as their linear analogs (L-PCLs), were synthesized by click chemistry in a number average molecular weight (Mn ) range of 2 to 22 kg/mol. They were investigated by polarized light optical microscopy (PLOM) and Differential Scanning Calorimetry (DSC). The nucleation and overall crystallization kinetics were studied, as well as their self-nucleation behavior and SSA (Successive Self-nucleation and Annealing) thermal fractionation. Cyclic PCLs were found to nucleate and crystallize faster than linear PCLs due to: (a) faster diffusion of C-PCL chains and (b) larger supercoolings of C-PCLs at any given crystallization temperature, as compared to L-PCLs. A bell shape curve was obtained when the overall crystallization rate was examined as a function of Mn, this effect is probably due to a competition between nucleation and diffusion. It was found for the first time, that since cyclic molecules have lower entanglement densities, they can quickly recover their pseudo-equilibrium compact coil conformations upon melting and therefore exhibit much smaller crystalline memory effects than their linear counterparts of identical chain lengths. SSA revealed that C-PCLs are more sensitive to annealing than L-PCLs because their ring topology and limited lamellar chain folding facilitates crystal thickening.


      PubDate: 2013-11-21T10:34:07Z
       
  • Editors and Editorial Board
    • Abstract: Publication date: December 2013
      Source:Reactive and Functional Polymers, Volume 73, Issue 12




      PubDate: 2013-11-13T10:34:45Z
       
  • Conferring pH-sensitivity on poly (vinylidene fluoride) membrane by poly
           (acrylic acid-co-butyl acrylate) microgels
    • Abstract: Publication date: Available online 9 November 2013
      Source:Reactive and Functional Polymers
      Author(s): Yang He , Xi Chen , Shiyin Bi , Weigui Fu , Congcong Shi , Li Chen
      In this paper, cross-linked poly (acrylic acid-co-butyl acrylate) microgels were utilized to impart pH-sensitivity to poly (vinylidene fluoride) membranes by phase separation of a casting solution of poly (vinylidene fluoride)/poly (acrylic acid-co-butyl acrylate)/DMF in aqueous solution. The effect of microgels content on morphologies, surface composition, and chemistry of the as-prepared membranes was studied by varieties of spectroscopic and microscopic characterization techniques. By using the filtration of water and protein aqueous solution, the performance of the membrane was evaluated. Results indicated that the as-prepared membrane was pH-sensitive to water flux, bovine serum albumin rejection and antifouling property. Besides,the as-prepared membrane showed an obvious improvement of water flux and proper bovine serum albumin rejection ratio, compared to the pristine PVDF membrane. Meanwhile, dynamic bovine serum albumin fouling resistance and flux recovery property were also greatly enhanced due to the improvement of surface hydrophilicity. Hopefully, the hydrophilic microgels additive would be favorable to fabricate other polymer membranes for water treatment.


      PubDate: 2013-11-13T10:34:45Z
       
  • Assembled diglycolamide for f-element ions sequestration at high acidity
    • Abstract: Publication date: Available online 1 November 2013
      Source:Reactive and Functional Polymers
      Author(s): Vivek Chavan , Vasudevan Thekkethil , Ashok K. Pandey , Mudassir Iqbal , Jurriaan Huskens , Sher Singh Meena , A. Goswami , Willem Verboom
      Diglycolamides (DGA) form reverse-micellar type of supramolecular aggregates upon equilibration with nitric acid solution that enhances DGA affinity extraordinary towards f-elements. To mimic DGA aggregates, DGA molecules have been preorganized on the chemical platforms to form assemblies having a good affinity towards f-elements. However, the synthetic procedures used are quite laborious that limits their large scale applications. To address this problem, a new DGA-bearing monomer N,N-dioctyl,N’-propyl-2-methylacrylamide diglycolamide has been synthesized. This DGA-methacrylate monomer can be polymerized easily, and shows an interesting affinity towards f-element ions both in monomeric and polymeric forms at high nitric acid concentrations. This makes it very promising for the development of fixed-site membranes, resins, and magnetic assemblies for a variety of applications. DGA-methacrylate monomer has been found to assemble on magnetic nanoparticles Fe3O4. This DGA-methacrylate coated Fe3O4 particles capture representative trivalent actinide 241Am with a very high efficiency. However, it has been observed that HNO3 induced preorganization of DGA-methacrylate plays an important role in sorption of f-element ions in the polymeric form and self-assembled molecules on magnetic nanoparticles.
      Graphical abstract image

      PubDate: 2013-11-05T10:40:55Z
       
  • Towards the Rational Design of Polymers using Molecular Simulation:
           Predicting the Effect of Cure Schedule on Thermo-mechanical Properties for
           a Cycloaliphatic Amine-Cured Epoxy Resin
    • Abstract: Publication date: Available online 24 October 2013
      Source:Reactive and Functional Polymers
      Author(s): Ian Hamerton , Winnie Tang , Jose V. Anguita , S. Ravi P. Silva
      We report prediction of selected physical properties (e.g. glass transition temperature, moduli and thermal degradation temperature) using molecular dynamics simulations for a difunctional epoxy monomer (the diglycidyl ether of bisphenol A) when cured with p-3,3’-dimethylcyclohexylamine to form a dielectric polymer suitable for microelectronic applications. Plots of density versus temperature show decreases in density within the same temperature range as experimental values for the thermal degradation and other thermal events determined using e.g. dynamic mechanical thermal analysis. Empirical characterisation data for a commercial example of the same polymer are presented to validate the network constructed. Extremely close agreement with empirical data is obtained: the simulated value for the glass transition temperature for the 60 °C cured epoxy resin (simulated conversion α = 0.70; experimentally determined α = 0.67 using Raman spectroscopy) is ca. 70-85 °C, in line with the experimental temperature range of 60-105 °C (peak maximum 85 °C). The simulation is also able to mimic the change in processing temperature: the simulated value for the glass transition temperature for the 130 °C cured epoxy resin (simulated α = 0.81; experimentally determined α = 0.73 using Raman and α = 0.85 using DSC) is ca. 105-130 °C, in line with the experimental temperature range of 110-155 °C (peak maximum 128 °C). This offers the possibility of optimising the processing parameters in silico to achieve the best final properties, reducing labour- and material-intensive empirical testing.


      PubDate: 2013-10-28T15:01:13Z
       
  • Bio- and bioelectro-catalytic properties of polyaniline/poly(acrylic acid)
           composite films bearing covalently-immobilized acid phosphatase
    • Abstract: Publication date: Available online 24 October 2013
      Source:Reactive and Functional Polymers
      Author(s): Toshimasa Homma , Mizuki Kondo , Takashi Kuwahara , Masato Shimomura
      Conducting films composed of polyaniline (PANI) and poly(acrylic acid) (PAA) were prepared by electrochemical polymerization of aniline in the presence of various concentrations of PAA. The content of PAA moiety on the surface of the composite films (PANI/PAA films) was estimated by determination of carboxyl groups and found to be controlled by the concentration of PAA in polymerization solution. Acid phosphatase (ACP) was immobilized covalently on the PANI/PAA films by the condensation reaction with the carboxyl groups on the films. It was confirmed that the enzyme activity of the ACP-immobilized PANI/PAA film increased with increasing content of PAA moiety on the surface of the film, accompanying an increase in the amount of the immobilized ACP. The activity of the covalently immobilized ACP was significantly higher than that of the ACP adsorbed on the PANI/PAA film. By use of the ACP-immobilized PANI/PAA film as an enzyme electrode, bioelectrocatalytic oxidation of L-ascorbic acid 2-phosphate (ASA2P) was examined. The enzyme electrode gave the current due to the oxidation of ASA2P in proportion to the content of PAA moiety on the surface of the PANI/PAA film used, which was relevant to the activity of the covalently immobilized ACP.


      PubDate: 2013-10-28T15:01:13Z
       
  • Synthesis, curing behavior and thermal properties of fluorene-containing
           benzoxazines based on linear and branched butylamines
    • Abstract: Publication date: Available online 24 October 2013
      Source:Reactive and Functional Polymers
      Author(s): Jun Wang , Tian-tian Ren , Yu-dan Wang , Xuan-yu He , Wen-bin Liu , Xian-de Shen
      A series of fluorene-containing benzoxazine monomers based on linear and branched butylamines were successfully synthesized in high purity and good yield through a facile one-pot procedure by the reaction of 9,9-bis-(4-hydroxyphenyl)- fluorene with paraformaldehyde and isomeric butylamines. The chemical structures of the target monomers were characterized by Fourier transform infrared (FT-IR), Elemental analysis, 1H and 13C nuclear magnetic resonance (NMR). The curing behavior of benzoxazine monomers was studied by differential scanning calorimetry (DSC) and FT-IR. The thermal properties of cured polybenzoxazines were measured by DSC and thermogravimetric analysis (TGA). The results reveal that the polarity of solvent and the basicity of butylamines produce clear effects on the synthesis of the butylamine-based benzoxazine monomers. Also, the basicity and steric effect of butylamines exhibit significant effects on the curing behavior of benzoxazine monomers and the thermal properties of their polymers. The glass transition temperature and thermal stability of branched butylamine-based polybenzoxazines are higher than those of the corresponding linear butylamine-based polybenzoxazine and traditional bisphenol A-based polybenzoxazines.


      PubDate: 2013-10-28T15:01:13Z
       
  • Polystyrene-supported triazoles for metal ions extraction: Synthesis and
           evaluation
    • Abstract: Publication date: Available online 24 October 2013
      Source:Reactive and Functional Polymers
      Author(s): Abid Ouerghui , Hichem Elamari , Saadia Ghammouri , Riadh Slimi , Faouzi Meganem , Christian Girard
      In order to prepare substituted polymers bearing functional groups to chelate metals for their application in extraction and/or depollution applications, Merrifield polymer was transformed into the known azidomethyl polystyrene. Click-chemistry based on copper (I)-catalyzed Huisgen’s reaction was then used to form polymer-grafted 1,4-triazoles using a variety of synthesized substituted alkynes. These polymer-supported triazoles were then used to extract metals (Cd, Fe, Mg, Ni and Co) from aqueous solutions. A comparative study of metal extractions by these supported triazoles was made between the starting azidomethyl polystyrene and two natural clays taken from the Gafsa area (South-West Tunisia). Raw and purified clays from two Gafsa sites were found to extract metals quite well with almost no selectivity, except for lower fixations of cadmium and magnesium. The synthesized polymers were found to extract all metals with lower efficiencies than the clays. However, one of the polymer-supported triazole was found to extract selectively cadmium with a high efficiency, reaching the levels of the natural clays.
      Graphical abstract image Highlights

      PubDate: 2013-10-28T15:01:13Z
       
  • High Glass Transition Temperature Bio-Based Copolyesters from
           Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and Isosorbide
    • Abstract: Publication date: Available online 17 October 2013
      Source:Reactive and Functional Polymers
      Author(s): Cédric Lorenzini , Estelle Renard , Julia Bensemhoun , Julien Babinot , Davy-Louis Versace , Valérie Langlois
      New renewable copolymers were prepared from reactive bis-hydroxylated poly(3-hydroxybutyrate-co-3-hydroxyvalerate) oligomers (PHBHV-diol), isosorbide and 1,4- phenylene diisocyanate. First, microwave (MW)-assisted alcoholysis in the presence of ethylene glycol provides a rapid and straightforward method for engineering PHBHV-diol, with molar masses ranging from 700 to 4100 g.mol-1. These well-defined oligoesters were further used for the preparation of random copolymers of PHBHV-diol and isosorbide bridged with 1,4-phenylene diisocyanate via urethanization. The molar masses (Mn) of most copolyesters are about 10000 g.mol-1 with polydispersities (DPI) in the range of 1.2-1.9. The dependence of the solid-state structures on the length of PHBHV block was carefully investigated. The incorporation of isosorbide units into the PHBHV backbone increased the glass-transition temperatures from +5°C up to +34°C.


      PubDate: 2013-10-20T09:37:21Z
       
  • Synthesis and Shape Memory Performance of Polyurethane/Graphene
           Nanocomposites
    • Abstract: Publication date: Available online 18 October 2013
      Source:Reactive and Functional Polymers
      Author(s): J T Kim , B K Kim , E Y Kim , H C Park , H M Jeong
      Small amounts of allyl isocyanate modified graphene (iG, 0-2.5 phr) were incorporated into acrylate terminated polyurethane (PU) by UV curing. The effects of this incorporation on the morphological, mechanical, thermal and shape memory properties of the nanocomposites were examined. The iG nanoparticles incorporated into the PU chains acted as both multifunctional crosslinkers and reinforcing fillers, and the effects were most pronounced at 1.5 phr iG. Consequently, the glassy and rubbery state moduli, yield strength, glass transition temperature (Tg), shape fixity and shape recovery ratios were increased by adding up to 1.5 phr iG. Above the loadings, most of the above properties decreased due to aggregation and the auto-inhibition reaction of allyl compounds.


      PubDate: 2013-10-20T09:37:21Z
       
  • Spider-Web-like Fiber toward Highly Oleophobic Fluorinated Materials with
           Low Bioaccumulative Potential
    • Abstract: Publication date: Available online 19 October 2013
      Source:Reactive and Functional Polymers
      Author(s): Pierre Conte , Thierry Darmanin , Frédéric Guittard
      Original fluorinated (F-butyl, F-hexyl and F-octyl) EDOT derivatives containing thioester connectors are synthesized and used as monomers for the elaboration of liquid-repellent surfaces by electrodeposition. Their surface morphology varies as a function of the fluorinated chain length, due to the increase in the insolubility of the oligomers formed in the first instances. Superhydrophobic surfaces are obtained with F-octyl and F-hexyl chains but only the surfaces produced from the monomer containing F-butyl chains are highly oleophobic. These high contact angles can be explained by their surface morphology (spider-web-like structure) which favors the “pinning effect”. This works allows the decrease in the bioaccumulative potential of fluorinated materials with an increase in their oil-repellent properties.
      Graphical abstract image Highlights Highly oleophobic properties are obtained by electrodeposition of original PEDOT derivatives containing F-butyl chains because their surface morphology (spider-web-like structure) favors the “pinning effect”.

      PubDate: 2013-10-20T09:37:21Z
       
  • Dual-network hydrogels based on chemically and physically crosslinked
           chitosan/chondroitin sulfate
    • Abstract: Publication date: Available online 19 October 2013
      Source:Reactive and Functional Polymers
      Author(s): André R. Fajardo , Silvia L. Fávaro , Adley F. Rubira , Edvani C. Muniz
      The formation of a novel type of hydrogel that combines chemically and physically crosslinked networks in a dual-network approach is presented here. Chitosan (CHT) and chondroitin sulfate (CS) were chemically modified with glycidyl methacrylate (GMA) and then crosslinked. The chemical hydrogels (CHT- and CS-gel) were deposited in different vials filled with CS or CHT stock solutions to form the dual-network hydrogels. FTIR, TGA and XRD analyses were used to characterize the chemical and the dual-network hydrogels. The percentages of CS or CHT complexed to the CHT- and CS-gel networks were calculated from the HPLC data. SEM images and swelling assays indicated that the formation of a secondary network by polyelectrolyte complexation changes the morphologies and liquid uptake capacities of the chemical hydrogels. Hence, the data and discussion presented here enable the formation of dual-network hydrogels with very interesting properties, such as the ability to interact with charged specimens (i.e., drugs, proteins or metal ions), a desirable feature for a wide range of applications.


      PubDate: 2013-10-20T09:37:21Z
       
  • Adsorption and desorption of calcium ions by temperature swing with
           copolymer of thermosensitive and chelating components grafted on porous
           ethylene vinyl acetate disk
    • Abstract: Publication date: Available online 9 October 2013
      Source:Reactive and Functional Polymers
      Author(s): Shuji Sakohara , Yusuke Kuriyama , Kensuke Kobayashi , Takehiko Gotoh , Takashi Iizawa
      A novel adsorbent composed of a copolymer of a thermosensitive component, N-isopropylacrylamide (NIPAM), and a chelating component, N-(4-vinyl)benzylethylenediamine (VBEDA), was developed, and the adsorption and desorption behaviors of Ca2+ ions were investigated. The copolymer of NIPAM and VBEDA was grafted onto the pore surfaces of a porous ethylene vinyl acetate (EVA) disk by a plasma-initiated polymerization method. The copolymerization ratios of VBEDA were 3 and 6 mol%. Although a hydrophilic component, VBEDA, was copolymerized with NIPAM, the transition temperature of the copolymer was almost the same as that of poly(NIPAM). The permeability through the polymer-grafted EVA disk strongly depended on the temperature. It was quite low below the transition temperature of the grafted polymer, and increased drastically when the temperature exceeded the transition temperature. The polymer-grafted EVA disk adsorbed Ca2+ ions at low temperatures and the adsorption amount decreased significantly when the temperature exceeded the transition temperature of the grafted polymer, and repeated adsorption and desorption by temperature swings were possible. Furthermore, it was suggested that one Ca2+ ion was captured by three VBEDA groups, and this multi-point coordination bond was destroyed by heating as a result of shrinkage of the grafted poly(NIPAM-co-VBEDA) chains, leading to desorption of Ca2+ ion.


      PubDate: 2013-10-12T09:34:54Z
       
  • Synthesis, Characterization and Self-Assembly of Hybrid pH-Sensitive Block
           Copolymer Containing Polyhedral Oligomeric Silsesquioxane (POSS)
    • Abstract: Publication date: Available online 9 October 2013
      Source:Reactive and Functional Polymers
      Author(s): Yiting Xu , Min Chen , Jianjie Xie , Cong Li , Cangjie Yang , Yuanming Deng , Conghui Yuan , Feng-Chih Chang , Lizong Dai
      In this study, a series of novel hybrid pH-sensitive block copolymers containing POSS (HBCPs), poly(methacrylisobutyl-POSS)-b-poly(4-vinylpyridine) (PMAiBuPOSS-b-P4VP) and poly(methacrylisobutyl-POSS)-b-polystyrene-b-poly(4-vinylpyridine) (PMAiBuPOSS-b-PS-b-P4VP), were synthesized via reversible addition fragmentation chain-transfer (RAFT) polymerization. Their structures and molecular weight were characterized via 1H NMR, GPC and TEM. Their self-assembly behaviors, including pH-sensitive behaviors and self-assembly morphologies in aqueous solution, were investigated via DLS and TEM. It was found that the size of aggregates in aqueous solution would initially decrease and later increase as the pH value increased. It is supposed that this behavior was caused by the pH sensitivity of the P4VP block of the HBCPs. Our hybrid triblock copolymers were found to assemble nanowires and nanospheres. Unique dot-like phase separation was also observed in the aggregates of the HBCPs at pH 1. Furthermore, we investigated the effects of block length and structure on the self-assembly morphologies of the HBCPs.


      PubDate: 2013-10-12T09:34:54Z
       
  • Influence of Sulfated Arabino- and Glucuronoxylans Charging-Behavior
           regarding Antithrombotic Properties
    • Abstract: Publication date: Available online 9 October 2013
      Source:Reactive and Functional Polymers
      Author(s): Simona Strnad , Nena Velkova , Bodo Saake , Aleš Doliška , Matej Bračič , Lidija Fras Zemljič
      During the last decade xylans were widely researched and several derivatives have been developed and analyzed. However, the application properties of these new products are still sparsely known. The main objective of the presented investigation was to examine whether sulfated xylans from different sources (hard wood and oat-spelt) possess antithrombotic properties and how their protonation/deprotonation behavior in water solutions influence these properties. Two types of xylans, glucuronoxylan derived from beech wood, and arabinoxylan from oat spelt, were sulfated. Infrared spectroscopy, elemental analysis, NMR and size exclusion chromatography were applied for analyzing the success of derivatization. Deprotonation/protonation behavior of xylan samples in water solutions was analyzed by titration methods and the antithrombotic properties were investigated using activated partial thromboplastin time determination. The results showed significant increases in negative charges for the sulfated samples, which were a consequence of introducing sulfated groups as strong acids. However, the increase of antithrombotic properties was not influenced only by the presence of certain amounts of sulfate functional groups but also by the total negative-charges originating from both sulfate and carboxyl groups. The later was proved by the high linear correlation between the activated partial thromboplastin time values, and the total charge of the samples.


      PubDate: 2013-10-12T09:34:54Z
       
  • Editors and Editorial Board
    • Abstract: Publication date: November 2013
      Source:Reactive and Functional Polymers, Volume 73, Issue 11




      PubDate: 2013-10-08T09:26:04Z
       
  • Concomitant cationic polymerization of a hybrid monomer and an epoxy resin
    • Abstract: Publication date: Available online 29 September 2013
      Source:Reactive and Functional Polymers
      Author(s): Andre Arnebold , Oliver Schorsch , Jens Beckmann , Andreas Hartwig
      The concomitant cationic polymerization of an epoxy resin and a hybridmonomer is a new concept for toughening epoxy resins. Thermolatent super acids are superior initiators of twin monomer polymerization and copolymerization. Determination of gel yield and instrumental characterization of the formed complex polymer network indicate that copolymerization occurs, integrating the linear silicone and novolak formed during twin polymerization into the epoxy network.


      PubDate: 2013-09-30T09:35:09Z
       
  • Effects of thermal history on the polymerisation mechanism and network
           development in aromatic polybenzoxazines
    • Abstract: Publication date: Available online 29 September 2013
      Source:Reactive and Functional Polymers
      Author(s): Ian Hamerton , Kallie Heap , Brendan J. Howlin , Lisa T. McNamara
      The effect of heating rate (2, 8 and 15 K/min) during the initial stages of cure of 2,2-bis(3,4-dihydro-3-phenyl-2H-1,3-benzoxazine)propane is examined. The rate of heating has a marked effect on the observed modulus, measured by DMTA, with the higher heating rate giving rise to an increase in storage modulus of ca. 1,000 MPa, although this is not accompanied by an increase in glass transition temperature. The thermal stability of the resulting polybenzoxazines also differs with the slower heating rate giving rise to less thermally stable structures. Data obtained from Raman spectroscopy (when combined with principal components analysis) suggests subtle changes in the mechanism during the early stages of reaction associated C-N-C and C-O moieties, some of which persist following a higher temperature postcure step leading to a crosslinked network with higher aliphatic character.


      PubDate: 2013-09-30T09:35:09Z
       
  • Synthesis and characterization of Triazole rich polyether polyols using
           Click Chemistry for highly branched Polyurethanes
    • Abstract: Publication date: Available online 20 September 2013
      Source:Reactive and Functional Polymers
      Author(s): Sasidhar kantheti , P.S. Sarath , Ramanuj Narayan , KVSN Raju
      The present work describes development of moisture cured polyurethane-urea coatings based on 1,2,3-triazole rich polyether polyols. In this paper, two polyether polyols were synthesized by using 1,3-dipolar azide-alkyne cycloaddition reaction and they were named as PL-1 and PL-2 where PL-1 is9 terminal hydroxyl groups and PL-2 is 6 terminal hydroxyl groups. These polyols were reacted with 4, 4’-diisocyanatodicyclohexylmethane (H12MDI) at OH: NCO ratio of 1:1.2 in order to obtain isocyanate terminated polyurethane prepolymers. The resulted prepolymers were casted on tin foil and cured under atmospheric moisture in order to get completely cured polyurethane-urea free films. The free films were characterized by using Fourier transformed infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and dynamic mechanical thermal analysis (DMTA) techniques. The TGA and DMTA results showed that these films have good thermal and mechanical stability. Anti-microbial studies proved that these polyurethane films show good resistance towards different bacterial and fungal attacks. These polymers were also coated on mild steel panels in order to evaluate corrosion resistance properties by using salt spray and electro chemical polarization studies.
      Graphical abstract image

      PubDate: 2013-09-26T14:04:41Z
       
  • Synthesis and Application of a Molecularly Imprinted Polymer as a Filter
           to Reduce Polycyclic Aromatic Hydrocarbon Levels in Mainstream Cigarette
           Smoke
    • Abstract: Publication date: Available online 26 September 2013
      Source:Reactive and Functional Polymers
      Author(s): Jiaqi Xie , Changqun Cai , Shenzhi Lai , Lin Yang , Lin Luo , Hui Yang , Yang Chen , Xiaoming Chen
      The design and fabrication of novel filter is a promising approach to realize the reduction of harmful substance in mainstream cigarette smoke. In our work, a kind of pyrene (PYR) imprinted polymer as a part of improved filter has been successfully synthesized for the determination of polycyclic aromatic hydrocarbons (PAHs) in mainstream cigarette smoke. The molecularly imprinted polymers (MIPs) showed an good affinity towards PYR with binding capacity (Qmax) of 18.33 mg/g. Accordingly, the MIPs were used as a solid phase extraction (SPE) sorbent for the extraction and enrichment of PAHs in mixed samples to evaluate the selectivity about the MIPs. When the cellulose acetate (CA)-filter was replaced by a MIPs-filter, the amount of PAHs in the mainstream smoke was reduced by 63.6%. The application will provide technical support for the design of functional filters to reduce the harms brought by cigarette suction.


      PubDate: 2013-09-26T14:04:41Z
       
  • Adsorption of rhodium(III) ions onto poly(1,8-diaminonaphthalene)
           chelating polymer: Equilibrium, kinetic and thermodynamic study
    • Abstract: Publication date: Available online 17 September 2013
      Source:Reactive and Functional Polymers
      Author(s): Tuğba Akkaya , Mustafa Gülfen , Uğursoy Olgun
      In the present work, poly(1,8-diaminonaphthalene) (poly(1,8-DAN)) was synthesized by the reaction of 1,8-diaminonaphthalene (1,8-DAN) with ammonium persulfate (APS) and then the equilibrium, kinetics and thermodynamics of rhodium(III) adsorption onto poly(1,8-DAN) were studied. Poly(1,8-DAN), Rh(III)-poly(1,8-DAN) and Rh(III)-1,8-DAN complex were characterized by UV-vis. and FTIR spectroscopy, thermal analysis, potentiometric titration and electrical conductivity. In the adsorption studies, the effects of acidity, the temperature and the concentration of rhodium(III) were examined. It was found that poly(1,8-DAN) has Rh(III) adsorption capacity (qm ) of 11.11 mg/g polymer. The adsorption data fitted better to the Freundlich isotherm then the Langmuir isotherm, and the kinetics of the adsorption fitted to pseudo second order kinetic model. The ΔG0 values were calculated as -7.33 at 20 and -11.31 kJ/mol at 60 0C. The enthalpy (ΔH0), entropy (ΔS0) and the activation energy (Ea ) of the adsorption were found as 21.335 kJ/mol, 97.057 J/mol.K and 70.210 kJ/mol, respectively. It was predicted that the adsorption of Rh(III) onto poly(1,8-DAN) was an endothermic chemical adsorption process governed by both ionic interaction and chelating mechanisms. It was also observed that the adsorption of Rh(III) lowered the electrical conductivity of the pol(1,8-DAN).


      PubDate: 2013-09-20T09:34:23Z
       
  • Chelating polymeric particles intended for the therapy of Wilson’s
           disease
    • Abstract: Publication date: November 2013
      Source:Reactive and Functional Polymers, Volume 73, Issue 11
      Author(s): Michaela Škodová , Jan Kučka , Miroslav Vetrík , Jan Skopal , Zuzana Walterová , Ondřej Sedláček , Petr Štěpánek , Jana Mattová , Pavla Poučková , Petr Urbánek , Martin Hrubý
      Wilson’s disease is a genetic disorder that leads to a high accumulation of copper in multiple organs with subsequent toxic effects. In this paper, a gentle therapy to eliminate harmful copper concentrations in patients with Wilson’s disease is proposed using an oral administration of insoluble polymeric sorbents containing selective chelating groups for copper(II). The sorbents contained triethylenetetramine, N,N-di(2-pyridylmethyl)amine, 8-hydroxyquinoline or 8-hydroxyquinoline-5-sulfonic acid chelating groups bound to a methacrylate-based macroporous support. Nearly quantitative copper(II) uptake within minutes was achieved in buffers modeling the pH range present in the gastric environment (pH 2.0 and 4.0). The sorbents demonstrated chelating selectivity for copper(II) against zinc(II) with ratios of up to 1321. The sorbents demonstrated sufficient stability of the copper complexes against rechelation using studies in a model environment for the small intestine (the presence of chelating amino acids, pH 6.8).


      PubDate: 2013-09-08T09:31:33Z
       
  • Mechanistic studies of protein refolding facilitated by like-charged
           polymers
    • Abstract: Publication date: November 2013
      Source:Reactive and Functional Polymers, Volume 73, Issue 11
      Author(s): Chun-Yan Yang , Xiao-Yan Dong , Yan Sun
      The mechanism of lysozyme refolding facilitated by like-charged polymers was studied using cationic polyelectrolytes of different molecular weights and structures. Lysozyme refolding yield increased with increasing the total charge ratio (R) of the charged polymer to lysozyme in the refolding solution till reaching a plateau at a critical total charge ratio (Rc ). The same Rc was observed for different polymers. Similarly, there was a critical minimum polymer molecular weight (Mc ) for the facilitated protein refolding, below which the refolding yield decreased. The refolding yield was independent of the charge group structures in polymer. Fluorescence spectroscopy revealed that the polymers had no effect on the protein folding kinetics. Two physical models were proposed to explain the mechanism of the facilitated refolding and the meanings of Rc and Mc . The facilitating effect was attributed to the electrostatic interaction-induced oriented alignment of multiple protein molecules near the polymer chains, which maximizes the electrostatic repulsion between neighboring protein molecules, leading to the inhibition of protein aggregation. The studies provided insight into the mechanism of like-charged polymer-facilitated protein refolding, which would help develop more efficient polymers/particles for facilitated protein refolding applications.


      PubDate: 2013-09-08T09:31:33Z
       
  • Alginate/BSA/montmorillonite composites with enhanced protein entrapment
           and controlled release efficiency
    • Abstract: Publication date: Available online 3 August 2013
      Source:Reactive and Functional Polymers
      Author(s): Hakan Kaygusuz , F. Bedia Erim
      Novel pH sensitive alginate–protein-clay composite beads were investigated for the in vitro oral delivery of the model protein, bovine serum albumin (BSA). X-ray diffraction (XRD) results revealed that BSA enter between layers of montmorillonite (MMT) by expanding interlayer distance and finally an exfoliated structure forms in the alginate hydrogel. MMT incorporation increases protein entrapment efficiency to 78%, compared to 40% of conventional alginate beads. The release ratio of BSA from composite beads is 9-13% depending on MMT contents after around a 2 hours stay in gastric fluid. More importantly, no BSA release is detected until 60-90 min after the first contact time of beads with gastric solution. The presence of clay in alginate beads prevents burst release in higher pH of intestine by slowing release rate of BSA to 45-55% within around 9 h, resulting in a potential matrix for intestinal release of protein drugs.


      PubDate: 2013-08-07T11:04:50Z
       
  • Antimicrobial surface coatings for polypropylene nonwoven fabrics
    • Abstract: Publication date: Available online 6 August 2013
      Source:Reactive and Functional Polymers
      Author(s): Idris Cerkez , S.D. Worley , R.M. Broughton , T.S. Huang
      Anionic and cationic N-halamine polyelectrolytes were synthesized, characterized and then immobilized onto melt-blown polypropylene fabrics having two different basis-weights. The coatings were rendered biocidal upon exposure to dilute sodium hypochlorite solution. The effect of single and multilayer deposition of the polyelectrolytes on the surfaces was investigated in terms of chlorine loadings, rechargeabilities, antimicrobial efficacies, and air permeabilities. It was found that all of the coatings provided remarkable biocidal efficacies with about six log reductions of bacteria within two min of contact time on filters having higher basis-weight, whereas slower inactivation was observed for lower-basis weight filters due to diminished surface areas and numbers of active halogen atoms. The antimicrobial coatings reduced the air permeabilities of the filters somewhat; however, the air permeabilities of the coated swatches were comparable to those of most protective textiles.


      PubDate: 2013-08-07T11:04:50Z
       
 
 
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